Predicting Alzheimer's: PET Scan Plus Memory Test Works Best

Combination of Brain Scans and Word-Recall Test Best for Predicting Dementia, but It's Expensive

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All Tests Were Predictive

The study participants were followed for nearly two years, during which time 28 received a diagnosis of Alzheimer’s disease.

All the tests were found to be significant predictors of progression to Alzheimer’s disease, but the combination of word-memory testing and PET scan was more predictive than any single test or other test combination.

The study appears in the June 30 online issue of Neurology. It was jointly funded by the National Institutes of Health and a consortium of pharmaceutical companies.

‘PET Cost Will Limit its Use’

Several previous studies have also concluded that PET scanning may be the best single test for predicting progression to Alzheimer’s. But the cost of the imaging test will limit its use, neurologist Carol F. Lippa, MD, writes in an editorial accompanying the study.

The cost of a PET scan is anywhere from $3,000 to $6,000 -- about twice the cost of MRI brain scans.

“One wonders if such extensive testing is realistic for clinical care when physicians are struggling to get their patients’ basic medications covered by insurance,” she writes.

Lippa tells WebMD the goal is to develop less costly predictors of progression to Alzheimer’s that are as good as or better than PET.

“We know this is a really good test,” she says. “But we also know that it is way too expensive to use to screen everybody over a certain age. The main value of PET may be as a reference to compare to new strategies.”